Method of consolidating wood by compression



Patel med Jan. 17,1922.

' W. R.,TURNBULL. METHOD OF CONSO LIDATING WOOD BY COMPRESSION.

APPLICATION FILED 050.4, 1919.

In/snug V 14. 77, T11)? ULL UNITED STATES PATENT OFFICE.

METHOD OF GONSOLIDATING- WOOD BY COMPRESSION.

Specification of Letters Patent. Patented Jan. 17, 1922.

Application filed December 4, 1919. Serial No. 342,454.

To all whom it may concern:

Be it known that I, WALLACE RUPERT TURNBULL, a subject of the Kin of Great Britain, a resident of the town 0 Rothesay, Province of New Brunswick, Dominion of Canada, have invented certain new and useful Improvements in Methods of Consolidatin Wood by Compression, of which the 0 lowing is a specification.

This invention relates to improvements in a method of preparing Wood by compression .so that while its density is increased its strength will be increased in a greater proportion, and thus the wood is adapted for use under conditions in which great strength is required in a small compass.

l have discovered that when natural wood is compressed in a direction across the grain or fibres, and parallel, or approximately parallel, to its annular rings, it is capable or withstanding a very great pressure, far exceeding its ordinary elastic limit in this direction, without seriously injuring the essential structure of the wood.

The wood so prepared has its strength increased in a greater roportion than its density is increased, and it is therefore possible to produce an artificial wood by this process or method, in which the elastic limit is greatly increased not only for stresses acting in the direction or the original compression load, but for other stresses such as end compression, bending, tension, shear, and the like.

This artificially prepared wood may have a greater strength than a natural wood of the same density, and may be used whenever it is desirable to use a wood of great strength in small compass, such as the lamina of wooden air propellers, the lugs or sleeves of variable pitch, air propel ers, etc.

It may also be used to advantage whenever it is desirable to employ a wood that is not liable to shrinkage, such as a wood xposed to heat, the liners of marine propelshait bearings, ste ler the case of artificially compressed wood not only s the strength increased, there a endency for to swell and n t to shrink ven when exposed to heat, and this may sometimes be of great advantage in certain cases oi required use.

According to this invention the wood be compressed across the grain paralle or approximately parallel to the direction of the annular rings, and this may be done either simply between flat plates, in which case the sides will bulge, or it may be done in a mould in which the sides are prevented from bulging, or in a mould in which both the sides and ends are prevented from bulg- 111g.

The accompanying illustrations show means whereby this consolidation of the wood is brought about, the annular rings being shown by dotted lines.

In the drawings:

Figure 1 shows a simple method of compressing the wood between, ressure plates.

Figure 2 shows a metho of compressing the wood in amould with sides to prevent any bulging of the sides of the wood.

Figs. 3 to 5 show a method of com-- pressing the wood in a mould having sides and ends to prevent bulging of the sides and. ends of the wood being treated.

In Figure 1 A and B represent pressure plates movable towards each other and (3 represents a piece of wood under compression by the said plates.

v The wood in this case may bulge laterally.

In Figure 2 the block 0 is located in a mould D having side walls E but open at the ends and a movable plate 15 compresses the block C in'the mould D, the side walls E preventing. bulging of the wood laterally, but as the mould is open at the ends, end bulging may take place.

it igs. 3 to 5 show a plan view, a side view, and a section on the line ab respectively of a mould for restricting side and end bulging. The mould G is provided with side walls H and end walls I and the block C is located in the mould and a pressure plate J is utilized for compressing the block of wood in the mould,

In this case compression takes place without Cgateral or end bulging of the block of woo Wood treated in this manner is increased in density and has its strength increased in a greater proportion than its density for stresses to which the wood may be suhected, so that a homogeneous product 18 thus obtained which will not shrinlr even when exposed to heat.

What l claim as my invention: The herein described method of preparing Mill blocks of wood having surfaces transverse the block lengthwise of the grain or at right to the annular rings in the wood, which ooman les to the annular rings. I 1 prises enclosing such blocks in such a man- 11 witness whereof I havehere'unto set my ner as to prevent their distortion lengthwise hand in the resence of two witnesses.--

to the gram and at right angles to the rings, WALLA E RUPERT TURNBULL. and applying pressure to such rings so as to Witnesses:

reduce or distort said annular rings without HENRY F. PUDDINGTON,

substantial variation of the dimension of HENRY W. ORWELL. 

